1. Field of the Invention
The present invention relates to a portable telephone and, more particularly, to a portable telephone with high radiation efficiency and high communication performance.
2. Description of the Related Art
In recent years, portable radio communication equipment typified by a portable telephone has rapidly come into wide use among people.
FIG. 15A is a perspective view showing the whole of a basic structure of a conventional and typical portable telephone, and FIG. 15B shows a structure of the portable telephone with an outer packaging removed and FIG. 15C shows a structure only of the outer packaging.
The conventional portable telephone at least includes an antenna 2, a metallic cabinet 3, a feeding point 4 and an outer packaging 5, and the antenna 2 is electrically connected to the upper end portion of the metallic cabinet 3 through the feeding point 4 connected to the lower end portion of the antenna. The outer packaging 5 is made of a material such as plastic or resin and constituted by a hollow cubic portion 5a and a cylindrical portion 5b disposed on the upper surface of the portion 5a, in which a round hole 5c whose size is equivalent to the diameter of the cylindrical portion 5b is provided on the surface of the cubic portion 5a in contact with the cylindrical portion, and a speech transmission unit and a speech reception unit are arranged on one of surfaces of the outer packaging 5. Within the outer packaging 5, the metallic cabinet 3, the feeding point 4 and the vicinity of the lower end portion of the antenna 2 are disposed and the antenna 2 is structured to project from the cylindrical portion 5b through the round hole 5c. Here, the axis of the antenna is made coincide with the z-axis and a width direction and a thickness direction of the metallic cabinet are made coincide with the x-axis and the y-axis, respectively. In addition, the surface of the metallic cabinet and the surface of the outer packaging are in parallel to each other and positioned on the plane xz.
For radiating an electromagnetic wave from the portable telephone, power is supplied to the antenna 2 and the metallic cabinet 3 by the application of power to the feeding point 4 to operate them as main radiation sources. Although a portable telephone in general has a mechanism for transmission and reception, a matching circuit for efficiently supplying power to the feeding point and the like which are mounted on the metallic cabinet, detailed view thereof is omitted from the illustration.
With the conventional portable telephone, a user makes a call through the speech transmission unit and the speech reception unit provided on the surface of the outer packaging 5 while holding the outer packaging by his or her hand. At this state, an electromagnetic wave radiated from the portable telephone is emitted into a space, propagated and received at a base station to enable communication. However, since of the electromagnetic waves radiated from the portable telephone, electromagnetic waves radiated toward a human body are liable to attenuate, the electromagnetic waves to this direction contribute less to communication to cause a reduction of radiation efficiency as a result. As described in the foregoing, conventional portable telephones have shortcomings that a reduction in the amount of electromagnetic waves contributing to communication degrades radiation efficiency of the portable telephones to degrade communication performance accordingly.
An object of the present invention is to provide a portable telephone with improved communication performance which is attained by increasing radiation efficiency of electromagnetic waves contributing to communication while a call is being made.
Another object of the present invention is to enable even a portable telephone required to be smaller in size and thinner to realize an increase in the amount of electromagnetic waves contributing to communication, thereby improving radiation efficiency during a call to achieve improvement in communication performance by using a reflecting plate also as an outer packaging of the portable telephone.
According to one aspect of the invention, a portable telephone including an antenna and a metallic cabinet operating as main radiation sources of electromagnetic waves, a feeding point for supplying the antenna and the metallic cabinet with electric power, an outer packaging formed of a material such as plastics or resin, and a reflecting plate for reflecting the electromagnetic waves radiated from the radiation sources, wherein
the reflecting plate is provided for increasing the amount of electromagnetic waves radiated into a free space when the portable telephone is in use, selectively arranged at a position where an electric field component or a magnetic field component of the electromagnetic waves radiated from the radiation sources is dominant, and has an electric constant which enables effective reflection of the magnetic field component or the electric field component and causes little electric power absorption.
In the preferred construction, the reflecting plate is contained in the outer packaging and provided in the vicinity of the radiation sources and on the side where a speech transmission unit and a speech reception unit are disposed.
In another preferred construction, the reflecting plate is a flat plate of a predetermined size and arranged in parallel to the metallic cabinet surface.
In another preferred construction, the reflecting plate is
contained in the outer packaging and provided in the vicinity of the radiation sources and on the side where a speech transmission unit and a speech reception unit are disposed, and
a flat plate of a predetermined size and arranged in parallel to the metallic cabinet surface.
In another preferred construction, the reflecting plate is a flat plate of a predetermined size and arranged aslant with respect to the metallic cabinet surface.
In another preferred construction, the reflecting plate is contained in the outer packaging and provided in the vicinity of the radiation sources and on the side where a speech transmission unit and a speech reception unit are disposed, and
the reflecting plate is a flat plate of a predetermined size and arranged aslant with respect to the metallic cabinet surface.
In another preferred construction, the reflecting plate is formed to be convex having a curvature at the side opposite to a direction in which the electromagnetic waves are incident and arranged to have a substantial vertex of the convexity face to the side of the radiation sources.
In another preferred construction, the reflecting plate is contained in the outer packaging and provided in the vicinity of the radiation sources and on the side where a speech transmission unit and a speech reception unit are disposed, and
the reflecting plate is formed to be convex having a curvature at the side opposite to a direction in which the electromagnetic waves are incident and arranged to have a substantial vertex of the convexity face to the side of the radiation sources.
In another preferred construction, the reflecting plate is bent to be V-shaped toward the side opposite to a direction in which the electromagnetic waves are incident.
In another preferred construction, the reflecting plate is contained in the outer packaging and provided in the vicinity of the radiation sources and on the side where a speech transmission unit and a speech reception unit are disposed, and
the reflecting plate is bent to be V-shaped toward the side opposite to a direction in which the electromagnetic waves are incident.
In another preferred construction, the reflecting plate is formed of a magnetic material having such a complex relative permeability as causes little power absorption of the electromagnetic waves radiated from the radiation sources.
In another preferred construction, the reflecting plate is formed of a dielectric material having such a complex relative dielectric constant as causes little power absorption of the electromagnetic waves radiated from the radiation sources.
In another preferred construction, the reflecting plate is provided in the plural including:
a reflecting plate formed of a magnetic material having such a complex relative permeability as causes little power absorption of the electromagnetic waves radiated from the radiation sources, and
a reflecting plate formed of a dielectric material having such a complex relative dielectric constant as causes little power absorption of the electromagnetic waves radiated from the radiation sources.
In another preferred construction, a reflecting plate formed of a magnetic material is disposed at a region where a magnetic field component of the electromagnetic waves generated from the radiation sources is dominant and a reflecting plate formed of a dielectric material is disposed at a region where an electric field component of the electromagnetic waves generated from the radiation sources is dominant.
In another preferred construction, a reflecting plate formed of a magnetic material is disposed to cover the vicinity of the feeding point and a reflecting plate formed of a dielectric material is disposed to cover the vicinity of a lower end portion of the metallic cabinet.
In another preferred construction, the reflecting plate is a reflecting plate formed of a magnetic material whose complex relative permeability at a frequency used in the portable telephone has a real part value larger than 1 and has an imaginary part value approximate to 0.
In another preferred construction, the reflecting plate is a reflecting plate formed of a magnetic material whose complex relative permeability at a frequency used in the portable telephone has a real part value larger than 1 and has an imaginary part value approximate to 0 and which has no conductivity.
In another preferred construction, the reflecting plate is a reflecting plate formed of a dielectric material whose complex relative dielectric constant at a frequency used in the portable telephone has a real part value larger than a value of a real part of a complex relative dielectric constant of the outer packaging and has an imaginary part value approximate to 0.
According to another aspect of the invention, a portable telephone including an antenna and a metallic cabinet operating as main radiation sources of electromagnetic waves, a feeding point for supplying the antenna and the metallic cabinet with electric power, and an outer packaging, wherein
the outer packaging is for increasing the amount of electromagnetic waves radiated into a free space when the portable telephone is in use and has a region where an electric field component or a magnetic field component of the electromagnetic waves radiated from the radiation sources is dominant partially provided with a material having an electric constant which enables effective reflection of the magnetic field component or the electric field component.
In the preferred construction, in the outer packaging,
a part of the surface of the outer packaging which is in the vicinity of the radiation sources and at the side where a speech transmission unit and a speech reception unit are disposed is provided with a region of a magnetic material whose complex relative permeability at a frequency used in the portable telephone has a real part value larger than 1 and has an imaginary part value approximate to 0 and the remaining part is formed of a material such as plastics or region.
In another preferred construction, in the outer packaging,
a part of the surface of the outer packaging which is in the vicinity of the radiation sources and at the side where a speech transmission unit and a speech reception unit are disposed is provided with a region of a dielectric material whose complex relative dielectric constant at a frequency used in the portable telephone has a real part value larger than a value of a real part of a complex relative dielectric constant of the material such as plastics or resin and has an imaginary part value approximate to 0 and the remaining part is formed of a material such as plastics or resin.
In another preferred construction, a magnetic field distribution and an electric field distribution in the vicinity of the radiation sources are evaluated in advance to form a part of the outer packaging at a region where a magnetic field component is dominant by using a magnetic material and a part of the outer packaging at a region where an electric field component is dominant by using a dielectric material, form the outer packaging by using the magnetic material and the dielectric material and form the remaining part by using such a material as plastics or resin.
Other objects, features and advantages of the present invention will become clear from the detailed description given herebelow.